Drug-Induced Sleep Endoscopy and Hypoglossal Nerve Stimulation Outcomes: A Multicenter Cohort Study

Neurostimulation for Pediatric Obstructive Sleep Apnea

Up to 80% of children with Down syndrome (DS) are affected by obstructive sleep apnea (OSA), and only 16% to 30% will have resolution of their OSA with adenotonsillectomy. Hypoglossal nerve stimulation is a well-established therapy for adults with OSA and was recently approved by the Food and Drug Administration for use in children with DS and residual OSA. There is robust experience with this therapy in adults that has led to well-established care pathways. However, given the challenges inherent to caring for a complex pediatric population, these pathways are not directly transferrable to children with DS.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities have been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, we provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with obstructive sleep apnea.

Exploring hypoglossal nerve stimulation therapy for obstructive sleep apnea: A comprehensive review of clinical and physiological upper airway outcomes

Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of upper airway collapse during sleep, which can lead to serious health issues like cardiovascular disease and neurocognitive impairments. While positive airway pressure serves as the standard treatment, intolerance in some individuals necessitates exploration of alternative therapies. Hypoglossal nerve stimulation (HGNS) promises to mitigate OSA morbidity by stimulating the tongue muscles to maintain airway patency. However, its effectiveness varies, prompting research for optimization. This review summarizes the effects of HGNS on upper airway obstruction from human and animal studies. It examines physiological responses including critical closing pressure, maximal airflow, nasal and upper airway resistance, compliance, stiffness, and geometry. Interactions among these parameters and discrepant findings in animal and human studies are explored. Additionally, the review summarizes the impact of HGNS on established OSA metrics, such as the apnea-hypopnea index, oxygen desaturation index, and sleep arousals. Various therapeutic modalities, including selective unilateral or bilateral HGNS, targeted unilateral HGNS, and whole unilateral or bilateral HGNS, are discussed. This review consolidates our understanding of HGNS mechanisms, fostering exploration of under-investigated outcomes and approaches to drive advancements in HGNS therapy.

Troubleshooting Upper Airway Stimulation Therapy Using Drug-Induced Sleep Endoscopy

OBJECTIVE

This study assesses the utility of drug-induced sleep endoscopy (DISE) in guiding further treatment for patients with obstructive sleep apnea (OSA) who have difficulty tolerating upper airway stimulation (UAS) or have inadequate response to therapy.

STUDY DESIGN

We conducted a retrospective analysis of UAS patients at our institution who underwent DISE, post-UAS, and evaluated the efficacy of different electrode configurations and maneuvers.

SETTING

A tertiary care hospital.

METHODS

Out of 379 patients who received UAS therapy, 34 patients who underwent DISE post-UAS (DISE-UAS) were included. Palatal coupling (PC) was assessed with UAS stimulation alone, jaw thrust alone, and both simultaneously during DISE.

RESULTS

Among 34 patients, 5 had suboptimal adherence to UAS therapy, 19 had suboptimal therapy efficacy with residual OSA burden, and 10 had both. During DISE-UAS, PC was observed in 7 patients (21%) with UAS stimulation alone, 9 patients (26%) with jaw thrust alone, and 8 patients (24%) with both maneuvers combined. Notably, 10 patients (29%) did not exhibit PC with any maneuver. Based on DISE-UAS findings, 13 patients were recommended oral appliance therapy (OAT), and 8 patients underwent further surgical interventions.

CONCLUSION

DISE-UAS is a valuable adjunct in troubleshooting UAS therapy for patients intolerant to CPAP or with suboptimal therapy efficacy. This study provides an algorithm for targeted multimodality therapy based on DISE findings, facilitating personalized management approaches.

The Repeatability of Pharyngeal Opening Pressure Under Drug-Induced Sleep Endoscopy

OBJECTIVE

Pharyngeal opening pressure (PhOP) is a measure of upper airway collapsibility that can be obtained during drug-induced sleep endoscopy (DISE) using a continuous positive airway pressure (CPAP) titration. However, the stability of PhOP over the course of sedation during DISE remains unclear. This study aims to compare repeat measures of PhOP over the course of DISE.

STUDY DESIGN

Single arm prospective study.

SETTING

Single tertiary care institution.

METHODS

Patients had 2 CPAP titrations while undergoing DISE. Collected data included patient demographics, PhOP, patient sedation index (PSI), and duration of and between CPAP titrations. t Tests, test-retest coefficient analysis, and repeated measures correlation were performed.

RESULTS

Twenty-five patients completed the study between 2022 and 2023 with 22 patients having sedation depth (PSI) recording. Most were male (76%), obese (average body mass index: 30.24 kg/m2), with severe obstructive sleep apnea (average apnea-hypopnea index: 39.8 events/hr). Test-retest analysis showed good-excellent correlation between PhOP values (intraclass correlation coefficient = 0.892, P < .0001, n = 25). Average time between CPAP titrations was 15 minutes to 6 seconds. Over that time, PhOP increased by an average of 0.72 cmH2O (P = .06, n = 25) and PSI decreased by 9.5 units (P = .01, n = 22). Repeated measures correlation showed a weak negative correlation between PhOP and PSI (r = -.45, P = .03, n = 22).

CONCLUSION

The results showed repeatability of PhOP values over the course of DISE. When adjusted for sedation depth (PSI), deeper sedation was weakly associated with greater PHOP. However, the magnitude of this change was small and we conclude that PhOP remains relatively stable over the course of DISE (Effects of Lung Volume on Upper Airway Patency During DISE [DISE-Pulm], NCT05350332, clinicaltrials.gov).

Pediatric Down Syndrome Upper Airway Stimulation: Patient Selection and Post-Implantation Optimization

OBJECTIVE

The Food and Drug Administration recently approved upper airway stimulation (UAS) for children with Down Syndrome and persistent obstructive sleep apnea who meet certain inclusion and exclusion criteria. Although there is a robust experience with this therapy in the adult population, established protocols used in adults are not directly transferrable to a complex pediatric population. This review aims to combine the protocols from several institutions for patient selection and postimplantation optimization, including a protocol for Drug-Induced Sleep Endoscopy in children with Down Syndrome, preactivation threshold measurements, device titration, and follow-up sleep studies.

STUDY DESIGN

Expert panel development of best Practice algorithm.

SETTING

Multi-institutional investigator review.

METHODS

An expert panel was assembled of pediatric otolaryngologists with extensive experience in hypoglossal nerve stimulation in children with Down Syndrome. Thirty statements were created during an initial drafting session. A modified Delphi method was used assess consensus among the panel.

RESULTS

After 2 rounds of Delphi surveys, 29 statements met criteria for consensus. One statement did not meet consensus. The statements were grouped into several categories to facilitate presentation.

CONCLUSIONS

A standardized approach to UAS for children with Down Syndrome must take into account the unique challenges inherent to treating a complex pediatric population with a high rate of sensory processing disorders. This expert panel has met consensus on several statements that will guide clinicians as this novel therapy is adopted.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea (OSA) requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities has been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, the authors provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with OSA.

Hypoglossal Nerve Stimulation Effects on Obstructive Sleep Apnea Over Time: A Systematic Review and Meta-analysis

OBJECTIVES

This study aimed to determine the efficacy of hypoglossal nerve stimulation (HGS) in the treatment of obstructive sleep apnea.

DATA SOURCES

PubMed, Cochrane database, Embase, Web of Science, SCOPUS, and Google Scholar.

REVIEW METHODS

Five databases were reviewed to identify relevant studies that measured polysomnography parameters such as the apnea-hypopnea index (AHI) and oxygen desaturation index, as well as quality of life and functional outcomes of sleep questionnaire scores, before and after HGS.

RESULTS

In total, 44 studies involving 8670 patients met the inclusion criteria. At 12 months after treatment, approximately 47%, 72%, and 82% of patients achieved AHI values of <5, < 10, and <15, respectively. The reported clinical success rates according to Sher criteria were 80% within 12 months and 73% between 12 and 36 months. While the favorable effects exhibited a gradual reduction up to 12 months postimplantation, they generally maintained a consistent level between the 12th and 36th months, as assessed by AHI < 5, <15, and success rate according to Sher criteria.

CONCLUSION

HGS can enhance quality of life scores and polysomnography outcomes in obstructive sleep apnea patients. Although the positive effects gradually decreased until 12 months after implantation, they generally remained consistent between 12 and 36 months.

The Impact of Hypoglossal Nerve Stimulation on Secondary Health Outcomes

Objectives: Obstructive sleep apnea (OSA) is a prevalent sleep disorder that can increase the risk of hypertension, diabetes, obesity, and cardiovascular diseases. Hypoglossal nerve stimulation (HGNS) is an alternative therapy for OSA in patients who cannot tolerate continuous positive airway pressure. Understanding the impact of HGNS on blood pressure, hemoglobin A1C (A1C), and body mass index (BMI) currently remains limited. Methods: A retrospective review study of HGNS outcomes at a single practice from January 2020 to November 2022 was conducted. Inclusion/exclusion criteria were based on HGNS eligibility and postoperative titration study. Statistical analysis and data management were performed using statistical software, R (v.4.2.1; R Core Team). Paired Student's T test, Fisher's exact test, and McNemar's exact test were utilized for statistical analysis. P values less than .05 were considered statistically significant. Results: Sixty-three patients were included in this study. A significant decrease in mean apnea-hypopnea index was noted following HGNS (mean change -28; P < .0001). Similar significant decreases were also seen in mean arterial pressures (mean change -8.4, P < .0001). There was a significant change in overall antihypertensive medication requirements and in requirements ≥3 medications (P < .0005, P = .03). There was a trend toward reduction in A1C; however, there was no change in BMI or number of diabetes medications taken. Conclusions: Our results reinforce previous findings that HGNS is an effective treatment option for carefully selected patients with OSA. In addition, our findings suggest that HGNS may improve patients' quality of life while minimizing OSA associated morbidity.

Palate shape is associated with Unilateral Hypoglossal Nerve Stimulation Outcomes

OBJECTIVE

The aim was to determine the potential association between palate shape and unilateral hypoglossal nerve stimulation (HNS) outcomes.

METHODS

Preoperative drug-induced sleep endoscopy (DISE) videos were reviewed and scored by 3 blinded reviewers to determine airway narrowing at the hard-soft palate junction (HP), soft palate genu, and inferior velum, as described by Woodson (2014). Scoring was as follows: 1-open airway, 2-narrow, 3-severe narrowing. Overall palate shape (oblique, intermediate, or vertical) was determined based on prior criteria. Successful surgical treatment was defined by the HNS titration polysomnogram as a reduction of ≥50% in the apnea-hypopnea index (AHI) to <15 events/h.

RESULTS

Of 332 adults, the majority was male (77%) with an average BMI of 29.2 ± 3.6 kg/m2 . Overall success rate was 73%. Success rate was lower in patients with vertical palate shape compared with the other shapes (56% vs. 75%, p = 0.029). HP score 3 compared with scores 2 and 1 was associated with lower success rates (60% vs. 76%, p = 0.028), but genu and velum scores were not associated with outcomes. Patients with both HP score 3 and complete oropharyngeal lateral wall-related obstruction had notably worse outcomes (22% vs. 74%, p = 0.026). HP score 3 (OR 0.45, 95%CI 0.22-0.92) and vertical palate shape (OR 0.33, 95%CI 0.15-0.78) were independently associated with lower odds of surgical response after adjustment for DISE findings, age, gender, and BMI.

CONCLUSION

Vertical palate shape and narrowing at the hard-soft palate junction are independently associated with lower HNS surgical success rates.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:981-986, 2024.

[Velopalatal coupling in sleep endoscopy: collapse-pattern based analysis of simulated airway opening]

OBJECTIVE

Drug-induced sleep endoscopy (DISE) is an established diagnostic procedure to assess the upper airway in patients with obstructive sleep apnea. During DISE airway opening is regularly simulated by various maneuvers. One of them is mandibular advancement by the modified jaw-thrust maneuver (MJTM).

MATERIAL AND METHODS

All DISE examinations evaluated by VOTE classification in the last 15 months were included. The effect of MJTM on anatomical levels was analyzed retrospectively. Frequency and type of collapse at the anatomic levels were recorded. Apnea-hypopnea index (AHI), body mass index (BMI), Epworth Sleepiness Scale (ESS) were determined.

RESULTS

61 patients were included (f=13, m=48, 54.3±12.9 y, ESS 11±5.5, AHI 30.2±19/h, BMI 29.7±4.5 kg/m2). A correlation of r=0.30 was found between AHI and BMI (p=0.02). At velum level, concentric collapse was detected in 16.4%, anterior-posterior (a.p.) collapse in 70.5%, and lateral collapse in 11.5%. A resolution of the collapse using the MJTM was observed in 75.5% of patients. However, in the presence of concentric collapse, opening was evident in 33.3% of cases in contrast to 86.5% in patients with a.p. collapse. Base of tongue collapse was resolved in 98.0% of the cases.

CONCLUSION

A correlation between the success of the MJTM on airway opening at the velum level and the pattern of palatal collapse was found. In therapies aimed at mandibular advancement, e.g. hypoglossal nerve stimulation, an effect on velopalatal airway opening has relevance, so optimization of preoperative diagnosis is of particular importance.

Should lateral wall collapse be a contraindication for hypoglossal nerve stimulation?

OBJECTIVE

The purpose of this study is to examine how lateral wall collapse affects treatment outcomes for hypoglossal nerve stimulation (HNS) patients.

METHODS

Patients (n = 111) queried from a single surgeon's database of HNS cases were divided into groups based on their degree of oropharyngeal lateral wall collapse noted on drug-induced sleep endoscopy (DISE): Complete, Partial, None. For each group, apnea hypopnea index (AHI) reduction, Epworth Sleepiness Scale (ESS) score, stimulation voltage, average nightly usage, need for alternate device configuration/awake sleep endoscopy, and rate of surgical success were collected. Patients with Complete collapse were compared to those with Partial/None via Student's t-tests and Pearson's Chi-square test.

RESULTS

Of the 111 eligible patients, 45 had complete, 30 partial, and 36 had no lateral oropharyngeal wall collapse. There were no statistically significant differences found between the Complete and Partial/None groups in terms of age, BMI, sex, AHI (pre and post-op), ESS (pre and post-op), voltage, alternate device configuration, or nightly adherence. Notably, a significantly greater number of the Partial/None group had surgical success (84.84 % vs 66.67 %, p = 0.024).

CONCLUSIONS

Patients with Partial/None oropharyngeal collapse were significantly more likely than patients with Complete lateral wall collapse to see surgical success. There are many factors to weigh when assessing a patient's surgical candidacy, it is clear that complete lateral wall collapse at the level of the oropharynx is a negative predictor for success in HNS.

A Critical Analysis of Pharyngeal Patterns of Collapse in Obstructive Sleep Apnea: Beyond the Endoscopic Classification Systems

(1) Background: Drug-Induced Sleep Endoscopy (DISE) enables the three-dimensional and dynamic visualization of the upper airway (UA) during sleep, which is useful in selecting the best treatment option for obstructive sleep apnea (OSA) patients, particularly for surgical procedures. Despite international consensus statements or position papers, a universally accepted DISE methodology and classification system remain a controversial open question. (2) Methods: A review of the English scientific literature on DISE related to endoscopic classification systems and surgical outcome predictors (3) Results: Of the 105 articles, 47 were included in the analysis based on their content's relevance to the searched keywords. (4) Conclusions: A final report and scoring classification system is not universally accepted; the most internationally applied endoscopic classification system during DISE does not cover all patterns of events that occur simultaneously during the endoscopic examination, highlighting that several configurations of collapse and obstruction at different UA levels could be observed during DISE, which should be described in detail if DISE has to be considered in the decision-making process for the UA surgical treatment in OSA patients and if DISE has to have a role as a predictive factor for surgical outcomes analysis.

Increased Body Mass Index Correlates with Less Favorable Postoperative Outcomes After Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea: A Retrospective Cohort Study

OBJECTIVE

Obstructive sleep apnea is associated with high morbidity. Hypoglossal nerve stimulation (HNS) has become a novel (neuro-) surgical treatment strategy for obstructive sleep apnea, demonstrating good success rates. Beyond predefined inclusion and exclusion criteria, no precise data are available, enabling individual preoperative risk assessment. To improve preoperative risk stratification, this study analyzed individual patient factors that affect outcomes of HNS.

METHODS

Fourteen patients treated with unilateral HNS were analyzed retrospectively. Assessed risk factors included: hypertension, diabetes mellitus, depression, smoking, alcohol consumption, body mass index (BMI), and disease duration. Treatment success was defined as a reduction in the postoperative apnea-hypopnea index (AHI) to ≤20 events/hour, with a relative reduction of at least 50% compared to baseline.

RESULTS

A significant reduction in the postoperative apnea-hypopnea index was observed in all patients (P < 0.0001). BMI correlated significantly with postoperative AHI scores (95% confidence interval, 0.1519-0.8974; P = 0.018). Significant treatment success was observed in 50% of patients. Compared with the "Excellent Responder group," the "Responder group" demonstrated a significantly higher BMI (95% confidence interval, 1.174-6.226; P = 0.0078). Diabetes, hypertension, disease duration, smoking, depression, and alcohol consumption were not significantly associated with AHI reduction.

CONCLUSIONS

Our findings suggest that BMI may be an independent risk factor for the response to HNS, with patients who had less benefit from therapy having significantly higher BMI than "Excellent Responders." Therefore, carefully selecting patients is crucial in obtaining optimal outcomes with HNS therapy, especially those with a high BMI.

The effect of velar collapse patterns on unilateral upper airway stimulation therapy

PURPOSE

Hypoglossal nerve stimulation is a promising alternative therapy for patients with obstructive sleep apnea with continuous positive airway pressure intolerance or failure. Previous studies concluded that a velar complete concentric collapse might prohibit a good therapeutic outcome. However, certain patients have an upper velar anteroposterior collapse and a lower velar complete concentric collapse. The effect of this velar collapse pattern is unknown, preventing evidence-based decision-making for these patients. This study aimed to compare the results of upper airway stimulation therapy in these patients to patients with a pure anteroposterior velar collapse.

METHODS

A retrospective single-center cohort study was performed. Patients were included who were implanted with an upper airway stimulation device and had a 1-year follow-up.

RESULTS

Of 66 patients, 10 had an upper velar anteroposterior collapse and lower velar complete concentric collapse. Fifty-six patients had a complete or partial velar anteroposterior collapse. At follow-up, all respiratory outcomes were similarly changed between the two groups. The mean apnea and hypopnea index reduced equally (26.9 events/hour vs. 23.9 events/hour, 95% CI (-5.0, 11.0), p = 0.46). A similar decrease in the oxygen desaturation index of ≥ 4% was observed (12.0/hour versus 11.5/hour, 95% CI (-8.7, 9.7) p = 0.92) CONCLUSION: Patients with an upper velar anteroposterior collapse and a lower velar complete concentric collapse are suitable candidates for upper airway stimulation therapy. In these patients, the lower velum may represent a transition zone between the anteroposterior collapse of the upper velum and the lateral collapse of the oropharynx, instead of being a real concentric collapse.

Obstructive Sleep Apnea

OBJECTIVE

Obstructive sleep apnea (OSA) is the most common type of sleep-disordered breathing. This article describes advances in the diagnosis, testing, treatment, and monitoring of OSA.

LATEST DEVELOPMENTS

Home sleep apnea testing and in-laboratory polysomnography are the most commonly used diagnostic tools in the identification and monitoring of OSA, but new methods for diagnosis and at-home monitoring of treatment response are being developed and validated. While the apnea-hypopnea index is regularly used to define OSA severity, recognition is increasing of its inability to risk-stratify patients. Other sleep study data including arousal threshold, hypoxic burden, and pulse rate variability as well as clinical characteristics can help with risk stratification. The most effective treatment is continuous positive airway pressure (CPAP), which can be limited by adherence and tolerance in some patients. Newer masks and comfort features including heated tubing and expiratory pressure relief may improve tolerance to positive airway pressure (PAP) therapy. Additional treatment options include other PAP modalities, mandibular advancement devices, tongue stimulation therapy, negative inspiratory pressure, nasal expiratory pressure valves, nasal congestion treatments, upper airway surgeries including hypoglossal nerve stimulation, and medications.

ESSENTIAL POINTS

OSA is a common disorder that causes sleep and daytime symptoms and increases the risk of neurologic and medical complications. Neurologists should be aware of atypical presentations and understand the diagnostic and treatment options.

Beyond CPAP: modifying upper airway output for the treatment of OSA

Obstructive Sleep Apnea (OSA) is exceedingly common but often under-treated. Continuous positive airway pressure (CPAP) has long been considered the gold standard of OSA therapy. Limitations to CPAP therapy include adherence and availability. The 2021 global CPAP shortage highlighted the need to tailor patient treatments beyond CPAP alone. Common CPAP alternative approaches include positional therapy, mandibular advancement devices, and upper airway surgery. Upper airway training consists of a variety of therapies, including exercise regimens, external neuromuscular electrical stimulation, and woodwind instruments. More invasive approaches include hypoglossal nerve stimulation devices. This review will focus on the approaches for modifying upper airway muscle behavior as a therapeutic modality in OSA.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

The Accuracy and Reliability of Visually Assessed Pharyngeal Opening Pressures During Drug-Induced Sleep Endoscopy

OBJECTIVE

To examine the accuracy and interrater reliability of a visually assessed vs airflow-based measure of pharyngeal collapsibility obtained in patients with obstructive sleep apnea undergoing drug-induced sleep endoscopy (DISE).

STUDY DESIGN

Prospective observational study.

SETTING

Academic tertiary care practice.

METHODS

Patients underwent DISE with airflow monitoring and nasal positive airway pressure titration to determine visual and airflow-based levels of pharyngeal opening pressure (PhOP). Visual DISE-PhOP was assessed by 2 blinded independent raters and defined as the pressure at which visual confirmation of airway collapse, including snoring, was abolished. Airflow-based DISE-PhOP was defined as the minimally effective positive airway pressure that abolished inspiratory flow limitation. Equivalence testing between visual and airflow DISE-PhOP of each rater was performed with the two one sided T-test (TOST) with an a priori equivalence bound of ±1 cm H2 O. Interrater reliability was evaluated with the intraclass correlation coefficient.

RESULTS

One hundred patients were enrolled in the study and 77 completed the full evaluation. The population was predominantly male (74%) with an average age of 54.8 years, body mass index of 30.1 kg/m2 , and apnea-hypopnea index of 30.7 events/h. Equivalence testing showed that both raters were within ±1 cm H2 O of airflow-based DISE-PhOP (-0.43 to 0.09 cm H2 O and -0.32 to 0.48 cm H2 O). Interrater reliability of visual DISE-PhOP between the raters was also good to excellent with an intraclass correlation coefficient of 0.895 (95% CI, 0.84-0.932).

CONCLUSION

DISE-PhOP, a measure of upper airway collapsibility, was equivalent between airflow-based and visual assessments with strong interrater reliability, supporting its adoption as a standardized objective parameter in clinical DISE.

Multilevel Airway Obstruction Phenotypes in Adult OSA

Objective

To describe multilevel phenotypes of airway obstruction identified on drug-induced sleep endoscopy (DISE) in adults.

Study Design

Retrospective chart review.

Setting

Tertiary care center.

Methods

Video recordings of DISE on adult patients were retrospectively scored. A cross-correlation matrix was created to detect significant correlations between DISE findings at anatomical subsites. Three multilevel phenotypes resulted from the matrix: complete collapse at the tongue base with complete collapse at the epiglottis (T2-E2), complete circumferential obstruction at the velum with complete lateral pharyngeal wall collapse at the oropharynx (V2C-O2LPW), and incomplete collapse at the velum with complete collapse due to tonsillar hypertrophy (V0/1-O2T). The mean difference (MD) and 95% confidence interval (CI) were calculated for demographic and polysomnogram metrics of each phenotype compared to all other subjects.

Results

Phenotype 1 (T2-E2) (n = 88) had older ages (MD 5.784 years, CI [1.992, 9.576]), lower body mass index (BMI) (MD -1.666 kg/m², CI [02.570, -0.762]), and smaller neck circumferences (MD -0.448 in., CI [-9.14, -0.009]) than the other phenotypes. Phenotype 2 (V2C-O2LPW) (n = 25) had higher BMIs (MD 2.813 kg/m², CI [1.362, 4.263]), higher neck circumference (MD 0.714 in., CI [0.004, 1.424]), and higher apnea-hypopnea index (MD 8.252, CI [0.463, 16.041]). Phenotype 3 (V0/1-O2T) (n = 20) had younger ages (MD -17.697, CI [-25.215, -11.179]).

Conclusion

Three distinct multilevel phenotypes of obstruction were identified on DISE, suggesting different anatomic subsites collapse in a nonrandom pattern. The phenotypes appear to represent distinct patient groups and their identification may have implications in terms of pathophysiology and treatment modalities.

Drug-Induced Sleep Endoscopy Findings and Hypoglossal Nerve Stimulation Therapy Outcomes

Hypoglossal-nerve stimulation (HGNS) is an established second-line therapy for patients with obstructive sleep apnea (OSA). Existing studies investigating the effect of preoperative drug-induced sleep endoscopic (DISE) findings on HGNS outcomes have mainly focused on the apnea/hypopnea index (AHI) among polysomnography (PSG) parameters, and have less frequently tested other PSG parameters such as the apnea index (AI), hypopnea index (HI), oxygen desaturation index (ODI), snoring index, and arousal index, or patient-reported excessive daytime sleepiness. The aim of this study was to investigate the correlation between DISE findings and the above-mentioned metrics after HGNS therapy. We only included patients with DISE findings providing detailed information about the degree of the anteroposterior velar (APV), oropharyngeal lateral wall (OPLW), or tongue-base (BT) obstruction based on the velum, oropharynx, base of tongue, and epiglottis (VOTE) classification. The data of 25 patients (9 female (36%)) were retrospectively evaluated. The mean age at the date of implantation was 54.52 ± 9.61 years, and the mean BMI was 29.99 ± 3.97 kg/m2. Spearman’s rho correlation coefficients were calculated. Significant correlations were found between the degree of APV obstruction and postoperative HI (r = −0.5, p < 0.05), and between the degree of OPLW obstruction and postoperative snoring index (r = 0.42, p < 0.05). BT obstruction was strongly correlated with postoperative metrics such as AHI (r = −0.57, p < 0.01), AI (r = −0.5, p < 0.05), ODI (r = −0.57, p < 0.01), ∆ AHI (r = 0.58, p < 0.01), ∆ AI (r = 0.54, p < 0.01) and ∆ ODI (r = 0.54, p < 0.01). No significant correlation was found between DISE findings and postoperative Epworth Sleepiness Scale values. These findings suggest that preoperative DISE findings, especially the degree of BT obstruction, are important for predicting an HGNS therapy outcome.

Use of drug-induced sleep endoscopy in Germany-an analysis based on claims data

Background

Drug-induced sleep endoscopy (DISE) has recently gained relevance as a diagnostic tool for obstructive sleep apnea (OSA). However, it is unclear to what extent and in which patient cohorts DISE is used in Germany. With introduction of specific coding for this method in 2021 (Operationen- und Prozedurenschluessel, OPS code), usage can now be analyzed based on diagnosis-related groups (DRG) claims data.

Methods

Aggregated data from all inpatient DISE procedures conducted in German hospitals in 2021 were obtained from the publicly available Institut fuer das Entgeltsystem im Krankenhaus (InEK) database. Patient-relevant information as well as data on hospitals providing the examinations were exported and analyzed.

Results

Between January and December 2021, a total of 2765 DISE procedures were conducted and documented using the newly introduced specific code (1-611.01). Most patients were male (75.6%), in the age categories 30-39 (15.2%) and 40-49 years (17.2%), and presented with the lowest patient clinical complexity level (PCCL; class 0 = 81.88%). Pediatric use was rare (1.8%). Leading main diagnoses of patients were G47.31 (OSA) and J34.2 (deviation of nasal septum). The most common procedures conducted together with DISE were nasal surgery, and the examination was mostly provided in large public hospitals with more than 800 beds.

Conclusion

Though the OSA prevalence in Germany is high, use of DISE as a diagnostic tool is low and represented only 4.4% of cases with a main diagnosis of OSA in 2021. Since specific coding was only introduced in January 2021, trends cannot yet be identified. Noticeable is the frequent combination of DISE with nasal surgery, which is not obviously related to a diagnosis of OSA. Limitations of the study are mainly related to the underlying data, which are available for the inpatient sector only, and due to potentially limited use of the OPS code, which was introduced recently and might not be known to all hospitals.

Objective Pharyngeal Phenotyping in Obstructive Sleep Apnea With High-Resolution Manometry

OBJECTIVE

Drug-induced sleep endoscopy (DISE) is a commonly used diagnostic tool for surgical procedural selection in obstructive sleep apnea (OSA), but it is expensive, subjective, and requires sedation. Here we present an initial investigation of high-resolution pharyngeal manometry (HRM) for upper airway phenotyping in OSA, developing a software system that reliably predicts pharyngeal sites of collapse based solely on manometric recordings.

STUDY DESIGN

Prospective cross-sectional study.

SETTING

An academic sleep medicine and surgery practice.

METHODS

Forty participants underwent simultaneous HRM and DISE. A machine learning algorithm was constructed to estimate pharyngeal level-specific severity of collapse, as determined by an expert DISE reviewer. The primary outcome metrics for each level were model accuracy and F1-score, which balances model precision against recall.

RESULTS

During model training, the average F1-score across all categories was 0.86, with an average weighted accuracy of 0.91. Using a holdout test set of 9 participants, a K-nearest neighbor model trained on 31 participants attained an average F1-score of 0.96 and an average accuracy of 0.97. The F1-score for prediction of complete concentric palatal collapse was 0.86.

CONCLUSION

Our findings suggest that HRM may enable objective and dynamic mapping of the pharynx, opening new pathways toward reliable and reproducible assessment of this complex anatomy in sleep.

Supine Pharyngeal Width Is Associated With Complete Concentric Palatal Collapse During Drug-Induced Sleep Endoscopy and Hypoglossal Nerve Stimulator Outcomes

OBJECTIVE

Hypoglossal nerve stimulation (HNS) implantation in the US requires preoperative drug-induced sleep endoscopy (DISE) screening for complete concentric palatal collapse (CCC) to establish treatment candidacy. We hypothesized that supine pharyngeal width (SPW) in awake patients is associated with CCC and HNS therapy outcomes.

METHODS

Adults with moderate to severe obstructive sleep apnea underwent awake measurement of SPW followed by DISE screening for CCC. Eligible patients electing for HNS implantation underwent postoperative polysomnography per standard of care.

RESULTS

SPW was measured in 73 patients. For SPW >20 mm, the positive likelihood ratio for absence of CCC was 6.67 with pre- and post-test odds of 6.3 and 42.0, respectively. Postoperative PSG data were available from 31 of 44 (70.5%) patients subsequently implanted with HNS. Patients with SPW >20 mm had a greater rate of HNS response than those with SPW ≤20 (62 vs 30%; P < .05). Only SPW and BMI were significantly associated with CCC and HNS response in regression models.

CONCLUSION

In a retrospective cohort study, SPW was significantly associated with CCC and postoperative apnea-hypopnea index following HNS implantation. SPW may be a viable screening tool for HNS candidacy.

The clinical application progress and potential of drug-induced sleep endoscopy in obstructive sleep apnea

Background and Objective: Obstructive sleep apnoea (OSA) is characterized by nocturnal repetitive upper airway (UA) collapse. For sleep physicians, the recognition of UA collapse characteristics is critical for understanding OSA mechanisms and developing individualized treatment plans. Drug-induced sleep endoscopy (DISE) is an exam during simulated sleep that allows the dynamic assessment of the UA of individuals with OSA. The initial recognition of DISE was to locate the sites of UA obstruction and direct the surgical selection of OSA since it was introduced in the 1990s. After approximately 30 years of studies, based on advances in endoscopic operative techniques and innovative treatments of OSA, DISE had been performed to explore mechanisms and comprehensive treatments related to UA collapse. Methods: This article reviewed contemporary DISE advances, including indications and contraindications, technique of induced sleep, endoscopic operation, UA characteristics classification.Results and Conclusions: Precise selection based on the association between collapse patterns and treatment modalities, such as continuous positive airway pressure, oral appliance, positional therapy, robotic surgery and neurostimulator implanting, is the future research prospect based on DISE.Key messagesDISE provides sleep physicians with valuable information about the upper airway collapse characteristics and dynamic changes during sleep.The studies based on DISE findings improve the selectivity and efficiency of treatment modalities, including classical therapies such as continuous positive airway pressure, oral appliance, positional therapy, and innovative therapies such as neurostimulator implanting and robotic surgery, promote the advancement of OSA precision medicine.

Association of hypoglossal nerve stimulator response with machine learning identified negative effort dependence patterns

Background

Hypoglossal nerve stimulator (HGNS) is a therapeutic option for moderate to severe obstructive sleep apnea (OSA). Improved patient selection criteria are needed to target those most likely to benefit. We hypothesized that the pattern of negative effort dependence (NED) on inspiratory flow limited waveforms recorded during sleep, which has been correlated with the site of upper airway collapse, would contribute to the prediction of HGNS outcome. We developed a machine learning (ML) algorithm to identify NED patterns in pre-treatment sleep studies. We hypothesized that the predominant NED pattern would differ between HGNS responders and non-responders.

Methods

An ML algorithm to identify NED patterns on the inspiratory portion of the nasal pressure waveform was derived from 5 development set polysomnograms. The algorithm was applied to pre-treatment sleep studies of subjects who underwent HGNS implantation to determine the percentage of each NED pattern. HGNS response was defined by STAR trial criteria for success (apnea–hypopnea index (AHI) reduced by > 50% and < 20/h) as well as by a change in AHI and oxygenation metrics. The predominant NED pattern in HGNS responders and non-responders was determined. Other variables including demographics and oxygenation metrics were also assessed between responders and non-responders.

Results

Of 45 subjects, 4 were excluded due to technically inadequate polysomnograms. In the remaining 41 subjects, ML accurately distinguished three NED patterns (minimal, non-discontinuous, and discontinuous). The percentage of NED minimal breaths was significantly greater in responders compared with non-responders (p = 0.01) when the response was defined based on STAR trial criteria, change in AHI, and oxygenation metrics.

Conclusion

ML can accurately identify NED patterns in pre-treatment sleep studies. There was a statistically significant difference in the predominant NED pattern between HGNS responders and non-responders with a greater NED minimal pattern in responders. Prospective studies incorporating NED patterns into predictive modeling of factors determining HGNS outcomes are needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11325-022-02641-y.

Cluster analysis of upper airway stimulation adherence patterns and implications on clinical care

Study Objectives

Upper airway stimulation (UAS) therapy is effective for a subset of obstructive sleep apnea (OSA) patients with continuous positive airway pressure (CPAP) intolerance. While overall adherence is high, some patients have suboptimal adherence, which limits efficacy. Our goal was to identify therapy usage patterns during the first 3 months of therapy to enable targeted strategies for improved adherence.

Methods

Therapy data was retrieved from 2098 patients for three months after device activation. Data included mean and standard deviation (SD) of hours of use, therapy pauses, hours from midnight the therapy was turned ON and OFF, percentage of missing days, and stimulation amplitude. Cluster analysis was performed using Gaussian mixture models that categorized patients into six main groups.

Results

The six groups and their prevalence can be summarized as Cluster 1A: Excellent Use (34%); Cluster 1B: Excellent Use with variable timing (23%); Cluster 2A: Good Use with missing days and late therapy ON (16%), Cluster 2B: Good Use with missing days, late therapy ON, and early therapy OFF (12%); Cluster 3A: Variable Use with frequent missing days (8%); Cluster 3B: Variable Use with frequent pauses (7%). Most patients (85%) are excellent or good users with mean therapy use &gt;6 hours per night.

Conclusions

Cluster analysis of early UAS usage patterns identified six distinct groups that may enable personalized interventions for improved long-term management. Differentiation of the patient clusters may have clinical implications with regard to sleep hygiene education, therapy discomfort, comorbid insomnia, and other conditions that impact adherence.

Hypoglossal Nerve Stimulation Therapy

Hypoglossal nerve stimulation (HNS) has been shown to be a safe alternative in the treatment of moderate-to-severe obstructive sleep apnea (OSA). A recent meta-analysis of 12 studies by Costantino et al. indicated the surgical success rates at 55-75%, a reduction of the apnea hypopnea index (AHI) of 18 events/h, and a reduction of the Epworth Sleepiness Scale (ESS) of 2.9-5.3. After animal studies in the 1970s, the first trial on humans to decrease upper airway resistance by transcutaneous electrical stimulation of the genioglossus was reported in 1989. A separate stimulation of protruding and retracting muscles was realized in 1995 by fine-wire electrodes that were placed into the tongue transoral. Over the next years, several companies developed implantable devices for hypoglossal stimulation in OSA. Initially, devices were developed that used unilateral stimulation of the hypoglossal nerve. In 2014, a device for unilateral respiratory frequency-controlled hypoglossal stimulation finally received FDA approval after a successful phase III trial. In recent years, a device for bilateral breath rate-independent stimulation of the hypoglossal nerve has been added to these approaches as a new development. Accordingly, hypoglossal nerve stimulation, on the one hand, is now an established tool for patients with OSA when standard treatments are not satisfactory. Beyond that, hypoglossal stimulation is undergoing a continuous and impressive development like hardly any other field of surgical therapy for OSA.

Comparison of Drug-Induced Sleep Endoscopy and Natural Sleep Endoscopy in the Assessment of Upper Airway Pathophysiology During Sleep: Protocol and Study Design

Study Objectives: Obstructive sleep apnea (OSA) is increasingly recognized as a complex and heterogenous disorder. As a result, a "one-size-fits-all" management approach should be avoided. Therefore, evaluation of pathophysiological endotyping in OSA patients is emphasized, with upper airway collapse during sleep as one of the main features. To assess the site(s) and pattern(s) of upper airway collapse, natural sleep endoscopy (NSE) is defined as the gold standard. As NSE is labor-intensive and time-consuming, it is not feasible in routine practice. Instead, drug-induced sleep endoscopy (DISE) is the most frequently used technique and can be considered as the clinical standard. Flow shape and snoring analysis are non-invasive measurement techniques, yet are still evolving. Although DISE is used as the clinical alternative to assess upper airway collapse, associations between DISE and NSE observations, and associated flow and snoring signals, have not been quantified satisfactorily. In the current project we aim to compare upper airway collapse identified in patients with OSA using endoscopic techniques as well as flow shape analysis and analysis of tracheal snoring sounds between natural and drug-induced sleep. Methods: This study is a blinded prospective comparative multicenter cohort study. The study population will consist of adult patients with a recent diagnosis of OSA. Eligible patients will undergo a polysomnography (PSG) with NSE overnight and a DISE within 3 months. During DISE the upper airway is assessed under sedation by an experienced ear, nose, throat (ENT) surgeon using a flexible fiberoptic endoscope in the operating theater. In contrast to DISE, NSE is performed during natural sleep using a pediatric bronchoscope. During research DISE and NSE, the standard set-up is expanded with additional PSG measurements, including gold standard flow and analysis of tracheal snoring sounds. Conclusions: This project will be one of the first studies to formally compare collapse patterns during natural and drug-induced sleep. Moreover, this will be, to the authors' best knowledge, the first comparative research in airflow shape and tracheal snoring sounds analysis between DISE and NSE. These novel and non-invasive diagnostic methods studying upper airway mechanics during sleep will be simultaneously validated against DISE and NSE. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT04729478.

Natural sleep endoscopy in obstructive sleep apnea: A systematic review

This study's objective is to systematically review the literature on natural sleep endoscopy (NSE), including the set-up, different scoring systems, visualized collapse patterns during natural sleep, additional measurements, and comparison of upper airway collapse between NSE and drug-induced sleep endoscopy (DISE). A computerized search on Medline, Web of Science and the Cochrane library was conducted, obtaining 39 hits. Ten prospective studies were included in which NSE was performed in adults with obstructive sleep apnea (OSA). This study's findings suggest the soft palate to be the most frequent site of obstruction (58.8 %), followed by the tongue base (43.2 %), lateral walls (29.9 %), and epiglottis (22.4 %), which is in line with previous findings during DISE. Based on this literature review, the authors conclude that at this stage high quality, comparative research between DISE and NSE is missing. To adequately compare findings between OSA patients, endoscopic classification of upper airway collapse should be standardized. Non-invasive predictive tools to determine pharyngeal collapse are currently under investigation and may obviate the need for invasive endoscopy. This review highlights the contribution of NSE in validating such novel diagnostic methods and in studying upper airway mechanics in a research setting, yet larger and adequately powered studies are needed.